Name: Planet EarthBirth Date: a very, very, very, long time agoVitals: Only planet in our solar system that has liquid water on surface,an atmosphere with mostly oxygen, and supports life...

2 It would be very easy to learn about the earth if scientists could locate a ready-made biographical sketch of our planet. However, it takes many scientists and numerous years of study to provide the information that we have and will continue to acquire about the earth. Let us examine some of the basic information about our planet's structure.3 Positioned as the third planet from the sun, scientists believe that earth was formed about 4.6 billion years ago. It is made mostly of rock, and about 70% of its surface is covered with a thin layer of water called a global ocean. Our planet from space looks like a blue sphere with cloud cover. However, Earth is actually an oblate spheroid or a slightly flattened sphere. (I guess those classroom globes made you think earth was a perfect sphere!) The Earth's oblate spheroid appearance is the result of it spinning on its axis. This spinning or rotation causes our planet's polar regions to flatten and our equatorial zone to bulge out. Our planet's circumference from pole to pole is 40,007 kilometers. Our equatorial circumference is 40,074 kilometers. You may not believe this, but the surface of our planet is relatively smooth. This means that the distances between our highest points (mountains) and our lowest points (ocean trenches) are small compared to our planet's size. In fact, the distance is about 20 kilometers. The average diameter of the earth is 12,756 kilometers. Now that we have looked at the surface, let us journey to the interior.